Building-block.



N0 MODEL,

PATENTBD JUNE 2,-1903.

P. BRAVNDNIER. BUILDING BLOCK.

APPLICATION FILED SEPT. 5, i902.

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between the first and last block.

4 Patented June 2, 1903.

PATENT OFFICE.

PAUL BRANDNER, OF BROOKLYN, NEW YORK.

BUILDING-BLOCK.

SPECIFICATION forming part of Letters Patent NO. 729,535, dated June 2,1903. Application filed September 5, i902. Serial No. 122,156. (Nomodel.)

To a, whom it mag concern:

Be it known that 1, PAUL BRANDNER, a citizen of the United States, and aresident of Brooklyn, county'of Kings, and State of New York, haveinvented certain new and useful Improvements in Building-Blocks, ofwhich,

the following is a specification.

In constructing chimneys and other round or curved structures itfrequently happens that the last or key block of a coursemust be chippedoff more orless in order to fit the gap In chimneys especially thatreceive a certain batter the width of this gap must necessarily change,so that even if the blocks are made to accurately fit any one coursethey cannot possibly fit accurately all the succeeding courses; but bycutting away the end of the blocks, as heretofore constructed, anylocking-flange formed on such end was also necessarily removed, andconsequently thelock-joint of the entire course was destroyed, so thatthe strength of the" structure was greatly inn paired. By my inventionthis objection is obviated, the block being so constructed that bycutting off its lock-joint end there is'exposed a new lock-joint endcorresponding in configuration to the original joint.

In the accompanying drawings, Figure l is a plan of a circular course ofbuilding-blocks embodying my invention. Fig. 2 is a perspective view ofa portion of a course. 'Fig. 3 is a top view of one of thebuilding-blocks; Fig. 4, a similar view showing a portion thereofremoved. views of a modification of the block.

The letters A A represent fireproof building-blocks adapted to formcurved structures and having arched front and rear sides and taperingends. These tapering ends are provided with suitable lock-joints adaptedto interlock with corresponding joints of the ad Figs. 5 and 6 arecorresponding Thus inFigs. 3 and 4: each or mortar key, by means otwhichthe blocks are locked together.

Now my invention consists in forming within the body of the blockperforations and intervening partitions s0 placed and shaped .that whenthe end of a block is cut ofi the joint on the raw end exposed willconstitute a substantial duplicate of the joint destroyed, or that, inother words, the locking device is latent within the body of the block.To effect this desirable result, the perforationsa within the body ofthe block are arranged in alinement with the grooves a, while theintervening partitions a are arranged in alinement with the tongues a.Thus if an arch is struck concentric to the frontorrear of the block topassthrough the centers of tongues Ct it will likewise pass through thecenters of partitions a, while a similar arch struck through centers ofgrooves a will pass through the centers of perforations a Each partitionand perforation corresponds, further, in ,shape and proportions to theshape and proportions of the tongue and groove, the edge of thepartition being inclined into parallelism with that of the tongue,-sothat consequently the eye of the perforation is inclined intoparallelism with the groove.

The result of the above construction is that if by a radial cut one endof the block is removed (dotted lines, Fig. 4) there will be at onceexposed a new edge,-which corresponds substantially in configuration tothe configuration of the edge'destroyed. In this way the block retainsits lock-joint edge and may be coupled to the adjoining block as thoughit were not mutilated. Consequently the blocksof each course may besecurely interlocked, while the point of weakness heretofore frequentlyfound at the terminal joint is entirely eliminated.

It is obvious that the form of the lock-joint and of the bodyperforations may be readily altered without departing from the spirit ofthe invention. Thus inFigs. 5 and 6the two central grooves a areconsolidated by chipping off the intervening section of partition a andadapting the enlarged groove thus formed for the reception of a key b.

What I claim is 1. A building-block provided with dovetail tongues andundercut grooves, and with oortapering body perforations in alinementwith respondingly shaped and proportioned body the grooves,substantially as specified. .o partitions and perforations, arranged inaline- Signed by me at New York city, New York, ment with the tonguesand grooves respecthis 4th day of September, 1902. tively, substantiallyas specified. PAUL BRANDNER.

2. A building-block provided with dovetail Witnesses: tongues andundercut grooves, tapering body F. V. BRIESEN,

partitions in alinement with the tongues, and WILLIAM SCHULZ.

